Adaptor with cam actuation



March 13, 1956. M. L. MOLEAN ET AL 2,738,483

ADAPTOR WITH CAM ACTUATION Filed April 1, 1952 4 E 77 f: 55 35 76 2 E 374 '5 28 1 a 30 70 INV NTO s 35 MARK MJEEAN HERBERT F. OVERMIER 37VATTORNEY United States Patent ADAPTOR WITH CAM ACTUATION Mark L. McLeanand Herbert F. Overmier, Emporium,

Pa., assignors to Sylvania Electric Products Inc., a corporation ofMassachusetts Application April 1, 1952, Serial No. 279,784

Claims. (Cl. 339-166) This invention relates to connectors and morespecifically to electrical connectors for use in adapting a radio tubesocket to receive vacuum tubes having lead-in connections which are notdesigned to fit that socket.

One of the features of the rapid growth of the electrical industry andmore particularly of the electronic industry in recent years has beenthe development of a wide diversity of radio tubes having a variety ofelectrical and mechanical characteristics. As the number of radio tubeshas multiplied in type there has been a proportional increase in thedifficulty of providing interchangeability, particularlyinterchangeability of the sort which permits the use of a given radiotube receiving socket with a tube type not originally constructed to fitthat socket. Such mechanical interchangeability is particularlydesirable in the production and servicing branches of the industry whereit is desirable to maintain simple equipments which are readilyadaptable to the processing, aging and testing requirements encounteredduring the process of manufacture of vacuum tubes of many types andduring the process of servicing equipments utilizing such tubes.

The present invention relates specifically to adaptors for use inconnecting electrical devices having a series of outward extendingflexible leads into connector devices designed to receive rigidconnecting leads, but the invention may be utilized in adaptors for usewith connectors of other types, including connectors utilizing rigidconnecting leads.

An object of the invention is to provide an adaptor for receivingelectrical leads and for making a firm mechanical and electricalconnection thereto. I A further object of the invention is the provisionof a vacuum tube adaptor in which flexible vacuum tube connecting leadsare readily received and then locked in place, and which in turn may beinserted into a given type of radio tube socket.

A still further object of the invention is the provision of a vacuumtube adaptor for receiving tubes having flexible leads which is simplein mechanical construction and economical to manufacture.

An even further object of the invention relates to a new and improveddevice for making connection to a vacuum tube having flexible connectingleads.

In accordance with one aspect of the invention an adaptor is constructedby providing a central post member having a base to which is attached aseries of suitably located rigid projecting pins adapted to engage aradio tube socket. The central member is cylindrical in generalconfiguration and has a number of longitudinally disposed connectinglead receiving grooves disposed about the periphery of, and generallyparallel to, the axis of the cylinder. Disposed within the longitudinalslots are springlike strip contact members individually connecting thebase pin connector members and having projections extending outwardly ofthe grooves for engaging a locking member. The locking member is anannular ring adapted to fit loosely over the cylindrical central member,

to slide longitudinally along it, and to compress the contact members,thereby forcing them into intimate engagement with the flexible vacuumtube leads.

In the drawings:

Fig. 1 is a view in partial cross section of an adaptor embodyingprinciples of the present invention and illustrating the use of theadaptor to provide connections to an octal type vacuum tube base.

Fig. 2 is a plan view of the embodiment of the invention illustrated inFig. 1.

Fig. 3 is a side view of the contact strip member shown in Fig. 1.

Fig. 4 is a front view of the contact strip member shown in Fig. 1.

Fig. 5 is a cross-sectional view of the embodiment of Fig. 1 takenthrough the locking ring at line 55.

Fig. 6 is a view in partial cross-section of another embodiment of theinvention.

Referring now to Figs. 1, 2 and 5 it will be seen that the invention inone embodiment utilizes as its principal supporting member cup-shapedmember 2 having a generally cylindrical wall rising perpendicularly frombase or closure member 4 which also serves as a support for flutedcentral core 6, socket connecting pins 8, and insulated key 10. Ingeneral, the configuration and disposition of pins 8 and key 10 will beidentical with that of a given type of vacuum tube base and adapted tofit a standard type of vacuum tube socket and to make engagement withthe connector receiving clips therein.

In the present embodiment of the invention the base constructionillustrated is that of an octal tube.

Surmounting the assembly comprising central core 6 and cup-shaped member2 is cover plate 12 having in it central aperture 14 and circularlydisposed conical apertures 16, the latter being disposed so as toprovide guides to aid in the insertion of flexible leads into theadaptor. Cover plate 12 is provided with overriding flange 17 andconical boss 18 to facilitate proper engagement with upper edges 20 andconical recess 22 of cup-shaped member 2 and core 6 respectively. Theassembly disc 12, core 6, and cup-shaped member 2 is held together byscrew 32 passing through aperture 14 in disc 12, through central bores24 and 26 of core 6, through bore 28 of base key 10 into threadedportion 30 of the base key 10.

Electrical connections within the adaptor are made by means of speciallyshaped strips mounted within longitudinal slots 36 which arecircumferentially disposed on core 6 and lie parallel to the axis ofcore 6. Strips 34 which are shown separately in Figs. 3 and 4 are formedof thin resilient sheet metal of a width approximately equal to that ofslots 36 provided to receive them. The lower ends 35 of strips 34 arenarrowed in order to permit their insertion directly into base contactpins 8 in order to simplify mechanical assembly. A soldered joint may beused to join strips 34 in pins 8 or the tips of 37 of strips 34 may beshaped as indicated in Figs. 3 and 4 to provide contact surface betweenstrip and pins While merely resting in pin 8. In the latter case, firmcontact is assured by the operation of the operating ring 38 asdescribed below.

As will be seen in the drawings it is desirable to shape contact strips34 in an irregular manner in order to provide contact surface 39 forleads from the vacuum tube being received by the adaptor, and toprovide, at the same time, a projecting surface 41 which extends beyondthe outer surface of cylindrical bore 6 into the space between thesurface of cylindrical bore 6 and the inner surface of cup-shaped member2. The projection thus provided serves as a gradually sloping camsurface upon which operating ring 38 may operate.

The structure of ring 38 may be seen by taking Figs.

.1 and 5 together. Locking ring 38 is provided with-inner cylindricalsurface 44 adapted to fit over the outer surface 45 of central core 6.Two lugs 40 are provided on ring 38 and extend outwardly therefrom inopposite directions, passing through slots 42 provided in the wall ofsupporting cup-shaped member 2. The axial length of inner cylindricalsurface 44 is sufiicient to provide a useful working surface capable ofpassing onto projecting portion 41 of spring contact 34 and of applyinga constant pressure thereto. Force applied to lugs 4% by the fingers ofthe user of the device is utilized to provide the necessary motion ofring 38 along the length of core 38, the travel of the ring beinglimited at the upper extreme by the inner surface of cover plate 12, andat the lower extreme by the bottoms of slots 42 which should be locatedso as to stop ring 38 with inner surface 44 at rest on the projectingportions of strips 34.

In operation, the invention is used as follows. The vacuum tube to beadapted to fit a socket which would otherwise be incapable of receivingit is placed so that its connecting leads pass individually into conicallead-in orifices 16 in cover plate 12. The leads pass through orifices16 downward into grooves 36 in central core 6. As the leads passdownward they encounter contact springs 34 at the points of inwardflexion 39 provided for this purpose. The leads may slide beyond thecontact portions of springs 34 to be received within the entire lengthof grooves 36, if necessary. After insertion of the tube leads into theadaptor, pressure is applied to outward extending lugs 40 to causepressure ring 38 to move downward within the adaptor body. As ring 38moves downward, the inner surface 44 of ring 33 presses against thesloping projection portions 43 of contact strips 34, thereby compressingstrips 34 into slots 36 and forcing the inwardly directed knees ofcontact strips 34 into close and intimate contact with the vacuum tubeleads. Passage of ring 38 downward is restricted only by frictionbetween the leading edge or the inner surface 44 of ring 38 and thesloping outer surface 43 of spring contact member 34. It will be seenthat, with continued downward motion of contact ring 38, innercylindrical surface 44 will eventually pass onto the projecting edge ofspring contact 34 so that the force of the spring action will bedirected in a direction perpendicular to surface 44, permitting ring 38to rest in the depressed position and at the same time, causing thecontact portion of springs 34 to remain in contact with the vacuum tubelead. The friction force thus exerted on the lead serves to retain it ingroove 36. Note that even though the spring contact 34 is compressedinto groove 36 by the operation of ring 38, the resilience of thecontact is not destroyed. The portion of the spring 34 above theprojecting knee 41 which extends to contact knee 39 is free to flex andadapted to fit conductors of various dimensions which the adaptor may becalled upon to receive.

Release of the vacuum tube from the adaptor is accomplished by reversingthe motion of retaining ring 38, accomplished by pressing upwards on theoutwardly extending ears 4%. Inner surface 44 of ring 38 thereuponbecomes disengaged from projecting portion 411 of spring 34, allowingthe spring to return to its outermost position. With release of thepressure upon spring 34 the restraining pressure is removed from thecontact lead within the groove, permitting withdrawal of the tube leadsfrom the adaptor socket.

Fig. 6 illustrates another embodiment of the invention in which a basedisc 50 is provided to support rigid connecting pins 52 in permanentrelationship to each other so that they are adapted to fit into a giventype of vacuum tube socket. Centrally disposed, and extendingperpendicularly from the center of disc 50, is fluted core section 54having narrow cylindrical upper section 56, tapered central section 58,and cylindrical base portion 60. Slots 62 are peripherally locatedaround core 54, having their innermost surfaces parallel to thelongitudinal axis of core 54. Surrounding the core and base assembly isouter shell 64 provided with upper thick wall portion 66, taperedcentral wall portion 68 and lower narrow wall portion 70. L slots 71 areprovided at two or more locations at the lower edge of outer shell 64and are adapted to engage locking pins 72 which extend outwardhorizontally from base 56. Located within the hollow space formedbetween narrow wall portion 70 of shell 64 and cylindrical base portion60 of core 54 immediately above base 50 are contact spring members 74which may be made of thin sheet metal. Contact membore 74 are adapted attheir lower ends to fit within contact pins 52 and are provided at theirupper ends with turned over portions 76 which extend into longitudinalgrooves 62 and at the same time make contact along the outer curvedsurface 77 of the turned over portion 76 with the tapered surface ofcentral tapered portion 68 of shell 64.

Operation of the adaptor of Fig. 6 is as follows: Outer shell 64 isrotated about the axis of the device so that pins 72 are moved to thevertical portion of L slots 71, thereby permitting vertical axial motionof outer shell 64 along core 56. With outer shell 64 thus moved upwardsthe disengagement of spring surfaces 76 from the bottom of slots 62 isinsured. The leads from the vacuum tube to be mounted in the adaptor arethen inserted into the grooves 62, passing within slots 62 to a pointbeyond that at which they will be engaged by the inner surface of curvedportion 76 of spring 74. Outer shell 64 is then forced downward to thelimit of L slot 71 and then turned to lock the shell, causing spring 74and curved portion 76 of spring 74 to be pressed inward into grooves 62.This motion is accomplished by the cam action of the inner surface oftapered portion 68 of outer shell 64 moving against surface of contactspring 74. Thus curved portion 76 of spring 74 is forced against thelead within slot 62 and, in turn, the lead is pressed against the bottomof slot 62, thereby holding the lead in place. While the turned overportion of spring 74 is compressed by this operation, it is not socompressed that it ceases to serve as a springthus providing tolerancefor receiving leads of different sizes. Removal of the tube from theadaptor is accomplished by reversing the process; namely, by rotatingthe shell so as to disengage pin 72 from the horizontal portion of the Lslots at its base, and permitting the upward motion of the outer shellwhich in turn relaxes the curved spring surfaces 76 from their positionagainst the contact leads. The tube may then be removed from theadaptor.

The embodiments of the invention described above are adapted to beconstructed out of a suitable insulating material such as a moldedplastic and the resulting adaptor is therefore well shielded so thataccidental contact with the voltage and current carrying portions of thedevice is avoided. In the case of the embodiment of Figs. 1 through 5the only metal parts needed within the assembly are contact pins 3,connector spring strips 34, and central assembly screw 32. In the caseof the embodiment of Fig. 6 the metal parts need only be contact pins52, flexible contact spring 74 and L slot guide pins 72.

While the invention has been described with reference to certainembodiments, it will be apparent to those skilled in the art that otherforms of the invention are possible. It is intended, therefore, that thebelow appended claims should be read and understood with a view to thefull appreciation of the spirit of the invention.

What we claim is:

1. In a device for adapting an electrical socket to receive flexibleconnecting leads the combination comprising a base portion having spacedconnector pins adapted to engage and make contact with receivingconnectors in a socket, a core disposed adjacent said base formed toprovide spaced longitudinal lead receiving slots, resilient conductivestrip members extending from said connector pins into the core slots,each of said strip members being-bent to form substantially the vertexof an angle adjacent the slot bottom and the vertex of a second angleexternal the slot, and a cam member mounted for slidable engagement withthe resilient strip portions external the core slots for urging eachconductive strip member toward the bottom of the slot.

2. In a device for adapting an electrical socket to receive connectingleads the combination comprising, a core formed to provide spacedlongitudinal lead receiving slots, a base portion having spacedconnector pins adapted to engage and make contact in an electricalsocket, resilient conductive strip members extending from the baseconnector pins into the core slots, each of said strip members beingbent to form a curved lead contact surface concave outwardly adjacentthe slot bottom and a curved surface concave inwardly external the slot,and a cam member mounted for slidable engagement with the resilientstrip portions external the core slot for urging each lead contactsurface toward the bottom of the slot.

3. In a device for adapting an electrical socket to receive connectingleads the combination comprising, a base portion having spaced connectorpins adapted to engage and make contact in an electrical socket, a coredisposed adjacent said base and formed to provide spaced longitudinallead receiving slots, resilient conductive strip members extending fromsaid connector pins into the core slots, each of said strip membersbeingbent to form a curved lead contact surface concave outwardly adjacentthe slot bottom and a curved surface concave inwardly external the slot,and a cam member mounted for slidable engagement with the resilientstrip portions external the 7 core slot for urging each lead contactsurface toward the bottom of the slot to. provide lead contact wipingaction. p

4. A device for adapting electrical sockets having a given configurationof pin receiving apertures the combination comprising a core formedtoprovide spaced longitudinal slots, a base portion disposed at one end ofsaid core having spaced connector pins adapted to be received by the pinreceiving apertures of a given socket, a resilient conductive stripmember partially positioned in each slot having one end connected to anassociated downwardly and outwardly internal the associated slotconnector pin, each resilient strip member being bent and adjacent theslot bottom to form a generally curved contact surface and being bent toform a sloping actuating surface external the slot, and a cam membermounted for slidable engagement with the actuating surface of said stripmembers for urging the contact surface of the strips toward the bottomof the slots, thereby providing wiping action between the strip contactsurface and any lead inserted along the slot bottom.

5. In an electrical connector for receiving leads the combinationcomprising a core formed to provide spaced longitudinal slots, a baseportion disposed at one end of said core having spaced fixed contacts, aresilient conductive strip member partially positioned in each slothaving one end connected to an associated fixed contact on the baseportion, each resilient strip member being bent internal the associatedslot downwardly toward and outwardly away from the slot bottom to form agenerally curved contact surface adjacent the slot bottom and being bentto form a sloping actuating surface external the slot, and a cam membermounted for slidable engagement with the actuating surface of said stripmembers for urging the contact surface of the strips toward the bottomof the slots, thereby providing Wiping action between the strip contactsurface and any lead inserted along the slot bottom.

References Cited in the file of this patent UNITED STATES PATENTS

